End of 2016-17 Season
Due to a rapidly dwindling snowpack, this will be the final advisory (avalanche outlook) of the 2016-17 season. This does not mean that avalanche season is over; avalanches can occur year round in Southcentral Alaska, and will definitely continue to occur in earnest over the next month or so as the mountains undergo their annual “shed cycle.” There is still a substantial amount of snow on northerly aspects, and northerly aspects have generally not yet started to “shed” with significant wet avalanche activity. Shedding (and significant wet avalanche activity) has commenced on east, south, and west aspects; but a lot of potentially dangerous snow remains.
Recently, temperatures have generally remained above freezing to ~2000′ day and night. Only a superficial nightly re-freeze has occurred in many areas above ~2000′. While recent cloud cover has limited the intensity of daytime warming, the lack of an overnight refreeze will keep wet avalanche danger elevated. Current conditions are most typical of what has been coined “all melt, no freeze” spring avalanche conditions (follow the link to learn more). These conditions are expected to continue for the near future.
Springtime avalanche conditions may change in Chugach State Park in the coming weeks, but given that it’s almost May “all melt, no freeze” is expected to be dominant. Check the weather resources to better understand what scenario is most likely to exist at a given time. Spring conditions that might be encountered in the next month (follow the links to learn more – listed from most to least likely):
All Melt, No Freeze: generally above freezing temperatures day and night with widespread wet avalanche danger that exists at all times, but increases further with daytime warming.
Melt-Freeze Cycles: clear and cold nights freezing the snowpack into a supportable crust that gradually softens through the day (ripe corn dependent on aspect and timing), and often becomes isothermal in the afternoon. Avalanche danger increases through the day, and decreases at night with cooling and darkness.
Cold & Snowy: a cold spring storm brings wintry weather. Widespread surface instabilities from new snow. Widespread wet avalanche activity when the sun comes out and affects new snow.
All Freeze, No Melt: unseasonably cold temperatures freeze the snowpack into a supportable crust, with limited diurnal melting (softening). Avalanche danger is reduced until significant warming and melting recommences.
Keep in mind that natural avalanches triggered in the upper elevations can affect lower elevation terrain (that might even be flat and snow-free). Many trails in Chugach State Park cross potentially dangerous avalanche paths.
Here are some important considerations when making plans to recreate this spring and early summer:
- Does your route cross avalanche terrain? Don’t forget to consider run-out zones (that might be even be flat and snow-free), from gullies and upper elevation slopes, especially if they could channel long-running avalanches that release in the upper elevations.
- Be on the lookout for recent (and perhaps even active) avalanche activity; this is an obvious warning to stay away from avalanche terrain and runout zones.
- Pay attention to the sun! The sun can heat up steep, solar aspects significantly. This can change conditions from generally safe to generally dangerous very rapidly.
- Be mindful of terrain traps that could make even a small avalanche’s debris pile up deeply enough to bury a person, cause a dangerous fall or loss of control, or cause traumatic injury. Learn from this report of a local high school teacher that died from a relatively small wet avalanche on Bird Ridge.
- The 2016-17 Chugach State Park snowpack is/was rife with persistent weak layers, especially the widespread basal layer of advanced facets and depth hoar. Recent natural wet slab avalanches have been observed across the park, in many cases triggered by small (and seemingly insignificant) wet loose avalanches or point releases. Persistent weak layers may continue to produce large slab avalanches throughout “shed season.”
- If you’re traveling on snow, especially in avalanche terrain (i.e. terrain steeper than 30 degrees, or in the runout of terrain steeper than 30 degrees), how wet is the snow? If there’s a supportable crust from recent freezing, avalanche danger will be lower (but keep in mind that steep, solar aspects above may be significantly wetter and more dangerous). If the snowpack is soft and mushy, especially if it’s unsupportable and you’re punching through or “postholing” due to isothermal snow, steep terrain and the runout of steep terrain will be dangerous.
- Rockfall is especially rampant in the spring and early summer!
Many avalanche accidents that have happened in Anchorage’s backyard of Chugach State Park could have been prevented by basic avalanche awareness. This level of awareness can be gained through a free or low-cost class. If you missed the many offerings earlier this season, make sure you take advantage of the numerous free and low-cost courses that will be offered in the fall. You can start learning with some free online resources here. Getting avalanche education is a big part of recreating safely on your vast and wondrous public land in Alaska, and being able to enjoy the mountains during the snow season will greatly enhance your life.
Here are links to further information on fatal avalanche accidents in Chugach State Park. You can learn from others’ mishaps.
The Anchorage Avalanche Center has concluded its fifth season of providing a grassroots, volunteer organized snow-season backcountry safety program for Chugach State Park.
Chugach State Park reportedly has no funding to support such a program, and other local avalanche organizations are only willing to support public observations hosted on the CNFAIC site (check to see how limited that information was this season).
If you think the backcountry snow community and Chugach State Park deserves more than just a public observations platform, please consider getting involved with (or donating to) the Anchorage Avalanche Center effort. Please consider soliciting support for the Anchorage Avalanche Center from your government representatives (Municipality of Anchorage and state level), the Department of Natural Resources (Alaska State Parks and Chugach State Park), and local businesses and organizations relevant to snow-season backcountry recreation. Your help is appreciated, and imperative for the development of a sustainable avalanche information program for Chugach State Park.
When the community decides to work together, Chugach State Park will have a sustainable snow-season backcountry safety program. The Anchorage Avalanche Center project has proved that a seasonal operating budget of only $20,000-30,000 is necessary for long term sustainability.
*click avalanche problem icons and hyperlinks for further info